pam_radius: buffer overflow in password field

add_password in pam_radius_auth.c in pam_radius 1.4.0 does not correctly check the length of the input password, and is vulnerable to a stack-based buffer overflow during memcpy(). An attacker could send a crafted password to an application (loading the pam_radius library) and crash it. Arbitrary code execution might be possible, depending on the application, C library, compiler, and other factors.